Expeditious synthesis of pyrano[2,3,4-de]quinolines via Rh(<scp>iii</scp>)-catalyzed cascade C–H activation/annulation/lactonization of quinolin-4-ol with alkynes
作者:Gang Liao、Hong Song、Xue-Song Yin、Bing-Feng Shi
DOI:10.1039/c7cc04113f
日期:——
One-step synthesis of tetracyclic pyrano[2,3,4-de]quinolones via Rh(iii)-catalyzed cascade C–H activation/annulation/lactonization is described.
Ca(II)-Catalyzed Cascade Reaction of Tryptamines with Propargylic Alcohols: Temperature-Driven Ring Opening and Closing via the Allene Migration Pathway for the Synthesis of Pyrrolo[1,2-<i>a</i>]indoles
作者:Ashok Kale、Su Jeong Kwon、Joohan Lee、Jae Kyun Lee、Kyeong Lee
DOI:10.1021/acs.orglett.3c04357
日期:2024.2.16
temperature-dependent cascade of reactions between tryptamines and propargylicalcohols was developed to achieve selective formation of pyrroloindoline and pyrrolo[1,2-a]indole heterocycles by Ca(II) catalysis. The cascade consists of electrophilic addition of allene at the C3 carbon of indole followed by intramolecular cyclization at 60 °C to yield pyrroloindolines. Furthermore, simultaneous 1,2-allene
开发了色胺和炔丙醇之间的温度依赖性级联反应,以通过 Ca(II) 催化选择性形成吡咯并吲哚啉和吡咯并[1,2- a ]吲哚杂环。该级联包括在吲哚的 C3 碳上进行丙二烯的亲电加成,然后在 60 °C 下进行分子内环化,生成吡咯并吲哚啉。此外,同时进行1,2-丙二烯迁移和吡咯烷开环,然后在回流温度下通过C-N键形成进行分子内环化,以获得吡咯并[1,2- a ]吲哚支架。该方案的优点是底物范围广泛、反应过程干净、可扩展性以及良好至优异的产率。
Rhodium‐Catalyzed Regioselective C—O and C—C Bonds Formation of 3‐Oxopent‐4‐enenitriles with Alkynes for the Synthesis of Polysubstituted 2H‐Pyrans
作者:Kelu Yan、Xiao Liu、Jiangwei Wen、Qiuyun Li、Junjie Wang、Yang Zheng、Xiu Wang
DOI:10.1002/cjoc.202400239
日期:2024.9
The rhodium-catalyzedC—Hbondactivation and cyclization of 3-oxopent-4-enenitriles with alkynes proceed efficiently. Various 2H-pyrans with multiple substituents are achieved in good yields through regioselective formation of C—O and C—C bonds. Transformations involving hydroxy-alkynoates resulted in products with a furo[3,4-b]pyran skeleton via further intramolecular ester exchange processes. Different
铑催化的 C—H 键活化以及 3-氧代戊基-4-烯腈与炔烃的环化反应高效进行。通过区域选择性形成CO和CC键,可以以良好的产率获得具有多个取代基的各种2H-吡喃。涉及羟基炔酸酯的转化通过进一步的分子内酯交换过程产生具有呋喃[3,4- b ]吡喃骨架的产物。与传统的“1-氧三烯途径”不同,该方法合成有用的2H-吡喃的方法在底物易得、产物稳定易衍生化、操作过程温和便捷、步骤和原子经济性等方面具有一定的亮点。
Synthesis of β-Allylbutenolides via One-Pot Copper-Catalyzed Hydroallylation/Cyclization of γ-Hydroxybutynoate Derivatives
Regioselective rapid triazole syntheses at low temperature are described. Organic azides and propargyl cations generated by acids gave fully substituted 1H-1,2,3-triazoles. Most reactions could be performed in 5 min at not only rt but also -90 degrees C. Both terminal and internal alkynes were acceptable, and the sterically bulky substituents could afford the products smoothly. Various types of three-component coupling reactions were demonstrated, and the presence of allenylaminodiazonium intermediates was indicated.